U.S. patent number 8,622,427 [Application Number 13/379,524] was granted by the patent office on 2014-01-07 for steering column support apparatus.
This patent grant is currently assigned to NSK Ltd.. The grantee listed for this patent is Takeshi Fujiwara, Takahiro Minamigata, Kiyoshi Sadakata, Toru Segawa, Osamu Tatewaki, Minao Umeda. Invention is credited to Takeshi Fujiwara, Takahiro Minamigata, Kiyoshi Sadakata, Toru Segawa, Osamu Tatewaki, Minao Umeda.
United States Patent |
8,622,427 |
Minamigata , et al. |
January 7, 2014 |
Steering column support apparatus
Abstract
Provided is a steering column support apparatus that simplifies
tuning for stabilizing the forward displacement of the steering
wheel during a secondary collision, and suppresses the absolute
value and variation of the break away load without strong rubbing
between the bracket 11 on the vehicle side and the bracket 33 on
the column side. By forming an extending section 57 on the top
plate section 55 of the bracket 33 on the column side, and a convex
curved surface 58 on the top surface of the front end section of
that extending section 57, a rise in contact pressure at the area
of contact that occurs when the edge on the front end of the top
surface of the top plate section 55 is pressed against the bottom
surface of the bracket 11 on the vehicle side by a moment that is
applied from the steering column 6c to the bracket 33 on the column
side during a secondary collision is suppressed.
Inventors: |
Minamigata; Takahiro (Gunma,
JP), Umeda; Minao (Gunma, JP), Fujiwara;
Takeshi (Gunma, JP), Tatewaki; Osamu (Gunma,
JP), Segawa; Toru (Gunma, JP), Sadakata;
Kiyoshi (Gunma, JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
Minamigata; Takahiro
Umeda; Minao
Fujiwara; Takeshi
Tatewaki; Osamu
Segawa; Toru
Sadakata; Kiyoshi |
Gunma
Gunma
Gunma
Gunma
Gunma
Gunma |
N/A
N/A
N/A
N/A
N/A
N/A |
JP
JP
JP
JP
JP
JP |
|
|
Assignee: |
NSK Ltd. (Tokyo,
JP)
|
Family
ID: |
46543619 |
Appl.
No.: |
13/379,524 |
Filed: |
October 17, 2011 |
PCT
Filed: |
October 17, 2011 |
PCT No.: |
PCT/JP2011/073850 |
371(c)(1),(2),(4) Date: |
February 14, 2012 |
PCT
Pub. No.: |
WO2012/063609 |
PCT
Pub. Date: |
May 18, 2012 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20120187669 A1 |
Jul 26, 2012 |
|
Foreign Application Priority Data
|
|
|
|
|
Nov 12, 2010 [JP] |
|
|
2010-253492 |
Nov 16, 2010 [JP] |
|
|
2010-256136 |
Nov 19, 2010 [JP] |
|
|
2010-258592 |
Nov 26, 2010 [JP] |
|
|
2010-263687 |
Dec 28, 2010 [JP] |
|
|
2010-293131 |
|
Current U.S.
Class: |
280/777; 280/779;
74/493 |
Current CPC
Class: |
B62D
1/195 (20130101) |
Current International
Class: |
B62D
1/19 (20060101) |
Field of
Search: |
;280/777,779,750
;74/492,493 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
1975037 |
|
Oct 2008 |
|
EP |
|
51119231 |
|
Sep 1976 |
|
JP |
|
51121929 |
|
Oct 1976 |
|
JP |
|
0169075 |
|
May 1989 |
|
JP |
|
20006821 |
|
Jan 2000 |
|
JP |
|
2002356168 |
|
Dec 2002 |
|
JP |
|
2003118602 |
|
Apr 2003 |
|
JP |
|
2005219641 |
|
Aug 2005 |
|
JP |
|
200769821 |
|
Mar 2007 |
|
JP |
|
2008018920 |
|
Jan 2008 |
|
JP |
|
2008100597 |
|
May 2008 |
|
JP |
|
2008213544 |
|
Sep 2008 |
|
JP |
|
2008247314 |
|
Oct 2008 |
|
JP |
|
2009227183 |
|
Oct 2009 |
|
JP |
|
2010089612 |
|
Apr 2010 |
|
JP |
|
2007046436 |
|
Apr 2007 |
|
WO |
|
2009121386 |
|
Oct 2009 |
|
WO |
|
Primary Examiner: Frisby; Keith
Attorney, Agent or Firm: Katten Muchin Rosenman LLP
Claims
What is claimed is:
1. A steering column support apparatus, comprising: a bracket on
the vehicle side having a locking hole that extends in the axial
direction of a steering column and that is located in the center
section in the width direction of the bracket, this bracket on the
vehicle side being supported by and fastened to the vehicle so as
not to displace in the forward direction during a secondary
collision; a bracket on the column side that is supported by the
steering column; and a locking capsule that is fastened to the
bracket on the column side, and in this fastened state, comprises a
locked section, both end sections thereof being locked inside the
locking hole, and a top side section that is formed on the top side
of the locked section and having a width dimension that is greater
than the maximum width dimension of the locking hole, and that in
fastened state, is located on the portion of the top side of the
bracket on the vehicle side on both sides of the locking hole, by
combining the locking capsule and the bracket on the vehicle side
when the portion of the bracket on the vehicle side on both sides
of the locking hole is held between the bottom surface of a flange
section of the locking capsule and the top surface of an underneath
support plate that is located below the flange section, the bracket
on the column side being supported by the bracket on the vehicle
side so as to be able to break away in the forward direction due to
an impact load that is applied during a secondary collision, and
means for suppressing a rise in contact pressure being further
provided, this means suppressing a rise in contact pressure that
increases at the area of contact between the front edge of the top
surface of the underneath support plate and the bottom surface of
the bracket on the vehicle side, when the front edge of the top
surface of the underneath support plate is pressed against the
bottom surface of the bracket on the vehicle side due to a moment
that is applied from the steering column to the bracket on the
column side during a secondary collision.
2. The steering column support apparatus according to claim 1,
wherein the bracket on the column side comprises a top plate
section that has a width dimension that is greater than the width
dimension of the locked section of the locking capsule, and that is
provided with the underneath support plate section that is located
below the flange section of the locking capsule; and together with
the bottom surface of the locked section of the locking capsule
coming in contact with the top surface of the top plate section of
the bracket on the column side, the portion of the bracket on the
vehicle side on both sides of the locking hole is held between the
bottom surface of the flange section and the top surface of the top
plate section.
3. The steering column support apparatus according to claim 1,
wherein the means for suppressing a rise in contact pressure is: an
inclined surface that is formed on the portion near the front end
on the top surface of the underneath support plate and is inclined
in a direction downward going toward the front edge of the
underneath support plate section, or an extending section that is
formed on the front end section of the underneath support plate
section and protrudes further toward the front than the edge on the
front end of the flange section.
4. The steering column support apparatus according to claim 3,
wherein the means for suppressing a rise in the contact pressure is
comprised of the extending section, the extending section provided
with an inclined surface that is formed on the portion near the
front end on the top surface of the extending section and is
inclined in a direction downward going toward the edge on the front
edge of the extending section.
5. The steering column support apparatus according to claim 1,
wherein a low-friction material layer made of a material that is
different from the metal of the underneath support plate and
bracket on the vehicle side, is provided at the area of contact
between the top surface of the underneath support plate and the
bottom surface of the bracket on the vehicle side so as to reduce
the coefficient of friction at the area of contact.
6. The steering column support apparatus according to claim 1,
wherein the length in the forward/backward direction of the locking
hole is longer than the length in the same direction of the locking
capsule, and is long enough that even when the locking capsule has
displaced in the forward direction, at least part of the locking
capsule is located on the top side of the front end section of the
bracket on the vehicle side, making it possible to prevent the
locking capsule from dropping down.
Description
TECHNICAL FIELD
The present invention relates to a steering column support
apparatus that supports a steering column such that the steering
column can displace in the forward direction with respect to the
vehicle body while absorbing impact energy that is applied to the
steering wheel from the body of the driver during a collision
accident.
BACKGROUND ART
A steering apparatus for an automobile, as illustrated in FIG. 31,
is constructed so that rotation of the steering wheel 1 is
transmitted to an input shaft 3 of a steering gear unit 2, and as
this input shaft 3 turns, the input shaft 3 pushes or pulls a pair
of left and right tie rods 4, which apply a steering angle to the
front wheels of the automobile. The steering wheel 1 is fastened to
and supported by the rear end section of a steering shaft 5, and
this steering shaft 5 is inserted in the axial direction through a
cylindrical shaped steering column 6, and is supported by this
steering column 6 such that it can rotate freely. The front end
section of the steering shaft 5 is connected to the rear end
section of an intermediate shaft 8 via a universal joint 7, and the
front end section of this intermediate shaft 8 is connected to the
input shaft 3 via a different universal joint 9. The intermediate
shaft 8 is constructed so that the shaft can transmit torque, and
can contract along its entire length due to an impact load, so that
when the steering gear unit 2 is displaced in the backward
direction due to a primary collision between an automobile and
another automobile, that displacement is absorbed, which prevents
the steering wheel 1 from displacing in the backward direction via
the steering shaft 5 and hitting the body of the driver.
In this kind of steering apparatus for an automobile, in order to
protect the body of the driver, this kind of steering apparatus for
an automobile requires construction that that allows the steering
wheel to displace in the forward direction while absorbing impact
energy during a collision accident. In other words, after the
primary collision in a collision accident, a secondary collision
occurs when the body of the driver collides with the steering wheel
1. In order to protect the driver by lessening the impact applied
to the body of the driver during this secondary collision,
construction is known (refer to JP51-121929(U), JP2005-219641(A)
and JP2000-6821(A)) and widely used in which an energy absorbing
member, which absorbs an impact load by plastically deforming, is
provided between the vehicle body and a member that supports the
steering column 6 that supports the steering wheel 1 with respect
to the vehicle body so that it can break away in the forward
direction due to an impact load in the forward direction during a
secondary collision, and displaces in the forward direction
together with the steering column 6.
FIG. 32 to FIG. 34 illustrate an example of this kind of steering
apparatus. A housing 10, which houses the reduction gear and the
like of an electric power steering apparatus, is fastened to the
front end section of a steering column 6a. A steering shaft 5a is
supported on the inside of the steering column 6a such that it can
only rotate freely, and a steering wheel 1 (see FIG. 31) can be
fastened to the portion on the rear end section of this steering
shaft 5a that protrudes from the opening on the rear end of the
steering column 6a. The steering column 6a and the housing 10 are
supported by a flat bracket on the vehicle side (not illustrated in
the figure) that is fastened to the vehicle body so that they can
break away in the forward direction due to an impact load in the
forward direction.
To accomplish this, a bracket 12 on the column side that is
supported in the middle section of the steering column 6a and a
support bracket 13 on the housing side that is supported by the
housing 10 are supported with respect to the vehicle body so that
they both can break away in the forward direction due to an impact
load in the forward direction. These support brackets 12, 13 both
comprise installation plate sections 14a, 14b at one to two
locations, and cutout sections 15a, 15b are formed in these
installation plate sections 14a, 14b so that they are open on the
rear end edges. With these cutout sections 15a, 15b covered,
sliding plates 16a, 16b are assembled in the portions of the
support brackets 12, 13 near both the left and right ends.
These sliding plates 16a, 16b are formed by bending thin metal
plate such as carbon steel plate or stainless steel plate provided
with a layer of a synthetic resin that slides easily, such as
polyamide resin (nylon), polytetrafluoroethylene resin (PTFE) or
the like on the surface into a U shape, having a top plate section
and bottom plate section that are connected by connecting plate
section. Through holes for inserting bolts or studs are formed in
the top and bottom plates in portions that are aligned with each
other. With these sliding plates 16a, 16b mounted on the
installation plate sections 14a, 14b, the through holes are aligned
with the cutout sections 15a, 15b that are formed in these
installation plate sections 14a, 14b.
The bracket 12 on the column side and the bracket 13 on the housing
side are supported by the fastening bracket 11 on the vehicle side
by screwing nuts onto bolts or studs that are inserted through the
cutout sections 15a, 15b in the installation plate sections 14a,
14b and the through holes in the sliding plates 16a, 16b, and
tightening the nuts. During a secondary collision, the bolts or
studs come out from the cutout sections 15a, 15b together with the
sliding plates 16a, 16b, which allows the steering column 6a and
the housing 10 to displace in the forward direction together with
the brackets 12 on the column side, the bracket 13 on the housing
side and the steering wheel 1.
In the example in the figures, energy absorbing members 17 are
provided between these bolts or studs and the bracket 12 on the
column side. As this bracket 12 on the column side displaces in the
forward direction, the energy absorbing members 17 plastically
deform so as to absorb the impact energy that is transmitted to the
bracket 12 on the column side by way of the steering shaft 5a and
steering column 6a.
As illustrated in FIG. 34, during a secondary collision, the bolts
or studs come out from the cutout sections 15 am 15b allowing the
bracket 12 on the column side to displace in the forward direction
from the normal state illustrated in FIG. 33, and the steering
column 6a displaces in the forward direction together with the
bracket 12 on the column side. When this happens, the bracket 13 on
the housing side as well breaks away from the vehicle body,
allowing this bracket 13 on the housing side to displace in the
forward direction. As the bracket 12 on the column side displaces
in the forward direction, the energy absorbing members 17
plastically deform and absorb impact energy that is transmitted to
the bracket 12 on the column side via the steering shaft 5a and the
steering column 6a, lessening the impact applied to the body of the
driver.
In the case of the construction illustrated in FIG. 32 to FIG. 34,
the bracket 12 on the column side is supported by the bracket on
the vehicle side at two locations, on both the right and left side,
so that it can break away in the forward direction during a
secondary collision. From the aspect of stable displacement in the
forward direction without causing the steering wheel 1 to tilt, it
is important during a secondary collision, that the pair of left
and right support sections be disengaged at the same time. However,
tuning in order that these support sections disengage at the same
time is affected not only by resistance such as the friction
resistance and the shear resistance to the disengagement of these
support sections, but unbalance on the left and right of the
inertial mass of the portion that displaces in the forward
direction together with the steering column 6a, so takes time and
trouble.
In order to stabilize the breaking away of the steering column in
the forward direction during a secondary collision, applying the
construction disclosed in JP51-121929(U) can be somewhat effective.
FIG. 35 to FIG. 37 illustrate the construction disclosed in this
document. In the case of this construction, a locking notch 18 is
formed in the center section in the width direction of a bracket 11
that is fastened to and supported by the vehicle body and that does
not displace in the forward direction even during a secondary
collision, and this locking notch 18 is open on the edge of the
front end of the bracket 11 on the vehicle side. Moreover, a
bracket 12a on the column side is such that it is able to displace
in the forward direction together with a steering column 6b during
a secondary collision.
Furthermore, both the left and right end sections of a locking
capsule 19 that is fastened to this bracket 12a on the column side
is locked in the locking notch 18. In other words, locking grooves
20 that are formed on both the left and right side surfaces of the
locking capsule 19 engage with the edges on the both the left and
right sides of the locking notch 18. Therefore, the portions on
both the left and right end sections of the locking capsule 19 that
exist on the top side of the locking grooves 20 are positioned on
the top side of bracket 11 on the vehicle side on both side
sections of the locking notch 18. When the bracket 11 on the
vehicle side and the locking capsule 19 are engaged by way of the
locking grooves 20 and the edges on both sides of the locking notch
18, locking pins 22 are pressure fitted into small locking holes
21a, 21b that are formed in positions in these members 11, 20 that
are aligned with each other, joining the members 11, 20 together.
These locking pins 22 are made using a relatively soft material
such as an aluminum alloy, synthetic resin or the like that will
shear under an impact load that is applied during a secondary
collision.
When an impact load is applied during a secondary collision from
the steering column 6b to the locking capsule 19 by way of the
bracket 12a on the column side, these locking pins 22 shear. The
locking capsule 19 then comes out in the forward direction from the
locking notch 18, which allows the steering column 6b to displace
in the forward direction of the steering wheel 1 that is supported
by this steering column 6b via the steering shaft.
In the case of the construction illustrated in FIG. 35 to FIG. 37,
the engagement section between the locking capsule 19 that is
fastened to the bracket 12a on the column side and the bracket 11
on the vehicle side is located at only one location in the center
section in the width direction. Therefore, tuning for disengaging
this engagement section and causing the steering wheel 1 to
displace stably in the forward direction during a secondary
collision becomes simple.
However, in the conventional construction, that shape of the
bracket 11 on the vehicle side is special, so the construction of
connecting and fastening this bracket 11a on the vehicle side to
the vehicle body becomes complex, and the assembly height becomes
high, therefore there is a problem in that design freedom of the
steering apparatus is lost. Moreover, the number of parts
increases, the work for processing parts, managing parts and
assembling parts becomes troublesome, and the costs increase.
Furthermore, the assembly height, for example, the distance from
the center of the steering column 6b to the installation surface on
the vehicle side becomes large, and there is a disadvantage in that
performing design in order that the steering column 6b does not
interfere with the knees of the driver becomes difficult.
Furthermore, construction for preventing the steering column 6a
from dropping excessively together with the steering wheel 1 when
the locking capsule has completely broken away from the bracket 11
on the vehicle side after a secondary collision is not
considered.
Furthermore, in the case of the conventional construction
illustrated in FIG. 35 to FIG. 37, reducing the load (break away
load) required in order for the locking capsule 19 that is fastened
to the bracket 12a on the column side to break away from the
locking notch 18 that is formed in the bracket 11 on the vehicle
side during a secondary collision is not particularly taken into
consideration. For example, the inside edges of the locking notch
18 that is formed in the bracket 11 on the vehicle side and the
edges on both the left and right sides of the locking capsule 19
directly face each other. During a secondary collision, there is
friction between the inside edges of the locking notch 18 and the
edges on both the left and right sides of the locking capsule 19
while the locking capsule 19 comes out in the forward direction
from the locking notch 18. Therefore, in order for the locking
capsule 19 to come out smoothly in the forward direction from the
locking notch 18 in order to lessen the impact that is applied to
the body of the driver during a secondary collision, it is
necessary to keep the friction force acting between the inside
edges of the locking notch 18 and the edges on both the left and
right sides of the locking capsule 19 low.
On the other hand, often in order to maintain necessary strength
and rigidity, the bracket 11 on the vehicle side is made by
punching and bending metal plate such as carbon steel plate using a
press. In regards to the inside edges of the locking notch 18,
fractured surfaces that occur while forming the locking notch by
punching remain. The surface roughness of the fractured surfaces is
large and thus friction resistance with opposing surfaces becomes
large, which is disadvantageous from the aspect of trying to lower
and stabilize the force required for the locking capsule 19 to come
out in the forward direction from the locking notch 18 during a
secondary collision.
Moreover, in regards to the locking capsule 19, in order to
sufficiently maintain reliability and durability of the connecting
section between the bracket 11 on the vehicle side and the bracket
12a on the column side, often the locking capsule 19 is made of a
metal material such as a ferrous metal like mild steel or an
aluminum alloy. By selecting the material for each part in this
way, friction occurs between metals of the bracket 11 on the
vehicle side and the locking capsule 19, including the friction
between inside edges of the locking notch 18 and the edges on both
the left and right sides of the locking capsule 19.
The friction coefficient in areas of friction between metal
materials is comparatively large. Therefore, depending on the
conditions of the secondary collision, in conditions where large
contact pressure is applied to the area of friction between the
locking capsule 19 and the locking notch 18, the load required for
the locking capsule 19 to come out in the forward direction from
the locking notch 18 increases a little. Moreover, when the locking
capsule 19 is made of a material such as synthetic resin or a light
metal alloy that is softer than the carbon steel plate of the
bracket 11 on the vehicle side, there is a possibility that the
inside edges of the locking notch 18, having exposed fracture
surface with large surface roughness, will bite into the side
surfaces of the locking capsule 19. In such a case as well, the
load required for the locking capsule 19 to come out in the forward
direction from the locking notch 18 increases a little.
Particularly, when a diagonal force in the forward direction is
applied to the locking capsule in a collision accident, large
contact pressure is applied at the area of friction between the
locking capsule 19 and the locking notch 18. As a result, the break
away load required for the locking capsule 19 to come out in the
forward direction from the locking notch 18 becomes large, and this
situation in which the break away load becomes large is not
desirable from the aspect of protecting the driver.
Furthermore, in the case of the construction illustrated in FIG. 31
to FIG. 34, in a tilt/telescopic steering apparatus having both a
tilting mechanism for adjusting the up/down position of the
steering wheel 1 and a telescopic mechanism for adjusting the
forward/backward position, the impact load that is transmitted from
the steering wheel 1 to the steering column 6a by way of the
steering shaft 5a during a secondary collision is input to the
bracket 12 on the column side by way of supported plate sections 32
of a bracket on the displacement side that is formed in part of the
steering column 6a and an adjustment rod 37 that is inserted though
long holes in the up/down direction in the support plate sections
34 of the bracket 12 on the column side. In other words, during a
secondary collision, this adjustment rod 37 presses strongly
against the inside edges on the front side of the long holes 35 in
the up/down direction. As a result, a moment in the clockwise
direction of FIG. 33 and FIG. 34 is suddenly applied to the bracket
12 on the column side with the adjustment rod 37 as the point where
the force is applied (input point) and the connection section
between the bracket 12 on the column side and the bolt that
connects this to the bracket on the vehicle side as the fulcrum.
Due to this kind of moment, the edge on the front end of the top
surface of the bracket 12 on the column side is strongly pressed
against the bottom surface of the bracket on the vehicle side. As a
result, a large friction force acts in this area, and the break
away load required for coming out from the bracket on the vehicle
side increases and displacement becomes unstable. Such a situation
is also undesirable from the aspect of protecting the driver.
The contact pressure that is applied at the area of contact between
the bracket 12 on the column side and the bracket on the vehicle
side becomes larger the larger this moment is, and this moment
becomes larger, the larger the distance is between the connection
section, which is the fulcrum, and the input section of the break
away load. This input section is where the inside edges of the long
holes in the up/down direction come in contact with the outer
circumferential surface of the adjustment rod 37, and this contact
area normally exists further below the main section of the steering
column 6a. Therefore, the distance between the connecting section
and the input section becomes large, the moment becomes large and
the contact pressure at the area of contact becomes high, so
reducing and stabilizing the breakaway load is difficult.
It is not presumed that the conventional construction illustrated
in FIG. 35 to FIG. 37 is applied to a tilt/telescopic type steering
apparatus, however, when this construction is applied to a
tilt/telescopic type steering apparatus, similar problems occur.
However, in the case of using a locking capsule 19 in which locking
grooves 20 are formed on the surfaces on the left and right sides
such as illustrated in FIG. 35 to FIG. 37, the bottom surface of
the bracket 11 on the vehicle side and the top surface of the
bracket 12a on the column side are sufficiently separated, so even
though a moment such as described above is applied to the bracket
12a on the column side during a secondary collision, the top
surface of the bracket 12a on the column side will not come in
contact with the bottom surface of the bracket on the vehicle
side.
Particularly, when the locking capsule 19 is made of a material
such as a light alloy or synthetic resin that is softer than the
steel plate of the bracket 11 on the vehicle side, an increase or
variation in the break away load due to the situation as described
above is suppressed to a certain extent. This is because, part of
the locking capsule 19 that is strongly pressed against the bottom
surface of the bracket 11 on the vehicle side by the moment
described above plastically deforms, causing the contact surface
area to expand and the contact pressure at that point to become
lower, and it is difficult for this part to bite into the opposing
surfaces. As a result, as the locking capsule 19 moves in the
forward direction, it becomes difficult for the top surface of the
bottom plate section that defines the bottom sides of the locking
grooves 20 of the locking capsule 19 to bite into the bottom
surface of the bracket 11 on the vehicle side, and it becomes
easier to keep the absolute value of the break away load and
variations in the load low.
However, even in the case where the locking capsule 19 is made of a
light alloy or synthetic resin, depending on the conditions, there
is a possibility that the locking capsule 19 will be affected by
the moment described above and it will not always be possible to
sufficiently lower the absolute value of the break away load and
variations in the load. Moreover, when the locking capsule 19 is
made of a ferrous alloy for the reason of maintaining strength and
rigidity, due to the same cause, there is a possibility that the
absolute value of the break away load or variations in the load
will become large.
JP01-69075(U) discloses construction wherein a bracket is welded
and fastened to the top surface of the steering column, and during
a secondary collision, there is impact between the edge on the
front end of this bracket and part of the edge on the rear end of
the bracket on the column side. With the construction disclosed in
this document, during a secondary collision, the moment applied to
the bracket on the column side is kept low, and the break away load
required for the bracket on the column side to come out in the
forward direction from the bracket on the vehicle side is kept low.
However, in the construction disclosed in JP01-69075(U), as in the
construction illustrated in FIG. 32 to FIG. 34, the bracket on the
column side is supported at two locations on the left and right by
the bracket on the vehicle side, so performing tuning in order to
stabilize forward displacement of the steering wheel 1 requires
time and trouble. Moreover, this construction does not make it
possible to prevent the steering wheel 1 from dropping excessively
after a secondary collision.
Of the related literature disclosing technology related to a
steering column support apparatus, JP2000-6821(A) discloses
construction wherein, in order to lessen the impact applied to the
body of the driver that collides with the steering wheel during a
secondary collision, an energy absorbing member that plastically
deforms as the steering wheel and steering column displace in the
forward direction is used. Moreover, in JP2007-69821(A) and
JP2008-100597(A), construction is disclosed wherein, in order to
increase the holding force for keeping the steering wheel in an
adjusted position, a plurality of overlapping friction plates are
used to increase the friction surface area. However, none of these
documents discloses technology for keeping the load required for
the locking capsule, which is supported by the steering column, to
come out in the forward direction from the locking notch, which is
formed in the bracket on the vehicle side, low.
RELATED LITERATURE
Patent Literature
TABLE-US-00001 [Patent Literature 1] JP51-121929(U) [Patent
Literature 2] JP2005-219641(A) [Patent Literature 3] JP2000-6821(A)
[Patent Literature 4] JP2007-69821(A) [Patent Literature 5]
JP2008-100597(A) [Patent Literature 6] JP01-69075(U)
SUMMARY OF THE INVENTION
Problem to be Solved by the Invention
In consideration of the situation described above, the object of
the present invention is to provide construction of a steering
wheel support apparatus that simplifies tuning for stabilizing
forward displacement of the steering wheel during a secondary
collision, keeps the absolute value of the break away load and
variation in the load low in order that there is no strong rubbing
between the bottom surface of the bracket on the vehicle side and
the top surface of the bracket on the column side or the locking
capsule, as well as increases the moment rigidity of the connecting
section between the locking capsule and the bracket on the column
side, and as necessary, prevents the steering wheel from dropping
excessively after a secondary collision.
Means for Solving the Problems
The steering column support apparatus of the present invention
comprises: a bracket on the vehicle side having a locking hole that
extends in the axial direction of a steering column and that is
located in the center section in the width direction of the
bracket, this bracket on the vehicle side being supported by and
fastened to the vehicle so as not to displace in the forward
direction during a secondary collision;
a bracket on the column side that is supported by the steering
column; and a locking capsule that is fastened to the bracket on
the column side, and in this fastened state, comprises a locked
section, both end sections thereof being locked inside the locking
hole, and a top side section that is formed on the top side of the
locked section and having a width dimension that is greater than
the maximum width dimension of of the locking hole, and that is
provided with a flange section which is located on the top side of
the portion of the bracket on the vehicle side on both sides of the
locking hole.
By combining the locking capsule and the bracket on the vehicle
side when the portion of the bracket on the vehicle side on both
sides of the locking hole is held between the bottom surface of the
flange section of the locking capsule and the top surface of an
underneath support plate that is located below the flange section,
the bracket on the column side is supported by the bracket on the
vehicle side so as to be able to break away in the forward
direction due to an impact load that is applied during a secondary
collision.
Particularly, in the steering column support apparatus of the
present invention, when the front edge of the underneath support
plate is pressed against the bottom surface of the bracket on the
vehicle side due to a moment that is applied from the steering
column to the bracket on the column side during a secondary
collision, there is means for suppressing a rise in contact
pressure that increases at the area of contact between the front
end on this top surface and the bottom surface of the bracket on
the vehicle side.
A locking capsule having a lower half section and an upper half
section, with the lower half section being the locked section, and
the upper half section being the top side section, is used as the
locking capsule. Together with the bottom surface of the locked
section (lower half section) of the locking capsule coming in
contact with the top surface of the top plate section of the
bracket on the column side, the portion of the bracket on the
vehicle side on both sides of the locking hole is held between the
bottom surface of the flange section and the top surface of the top
plate section. In other words, the portion of the top plate section
of the bracket on the column side that is underneath the flange
section corresponds to the underneath support plate section.
An inclined surface that is formed on the portion near the front
end on the top surface of the underneath support plate and that is
inclined in a direction downward going toward the front edge of the
underneath support plate section, or an extending section that is
formed on the front end section of the underneath support plate
section and protrudes further toward the front than the edge on the
front end of the flange section can be used as the means for
suppressing a rise in contact pressure.
In the form that employs an inclined surface, the inclined surface
can preferably be a convex curved surface having an arc shaped
cross section (partial cylindrical surface). More preferably,
construction is used where the arc that expresses the
cross-sectional shape of the convex curved section and a straight
line that expresses the cross-sectional shape of the portion on the
top surface of the underneath support plate section from the middle
section to the portion near the base end are connected smoothly, or
in other words, this straight line is connected in the tangential
direction of the arc.
The two forms above can be combined. In other words, in a form that
employs an extending section, an inclined surface that is inclined
in a direction downward going toward the edge on the front end of
the extending section is formed on the portion near the front end
on the top surface of the extending section.
In the present invention, preferably a low-friction material layer
made of a material that is different from the metal of the
underneath support plate and bracket on the vehicle side, is
provided at the area of contact between the top surface of the
underneath support plate and the bottom surface of the bracket on
the vehicle side so as to reduce the coefficient of friction at the
area of contact.
Furthermore, in the present invention, preferably the length in the
forward/backward direction of the locking hole is longer than the
length in the same direction of the locking capsule. More
specifically, the length in the forward/backward direction of the
locking hole is long enough that even when the locking capsule has
displaced in the forward direction, at least part of the locking
capsule is located on the top side of the front end section of the
bracket on the vehicle side, making it possible to prevent the
locking capsule from dropping down.
Moreover, preferably, at least the edges on the left and right
sides of the rear end section of the locking hole are shaped so as
to incline toward each other going toward the rear.
In another form of the steering column support apparatus of the
present invention, alternatively or additionally, the following
construction can be employed as a way of keeping the absolute value
and variation of the break away load low. In other words, in this
form, in construction in which the bracket on the column side
comprises a pair of left and right support plate sections and a top
plate section that connects the edges on the top ends of these
support plate sections, the steering column is supported and the
locking capsule is supported by and fastened to the top surface of
the top plate section, by holding the middle section of the
steering column between these support plate sections, and further,
by applying a force by a rod shaped member, which is located
further below than the steering column, in a direction that reduces
the space between the support plate sections, a pair of protruding
pieces are fastened to a portion of the middle section of the
steering column on the rear side of the pair of left and right
support plate sections of the bracket on the column side so as to
protrude from the surfaces on the left and right sides of the
steering column toward the left and right sides, and by causing the
edges on the front sides of these protruding pieces to face the
edges on the rear sides of the support plate sections at portions
located above the rod shaped member, the impact load that is
transmitted from the steering column to the bracket on the column
side during a secondary collision is transmitted by way of the area
of contact between the front edges of the protruding pieces and the
rear edges of the support plate sections without going through the
rod shaped member.
Preferably, the height positions of the protruding pieces are the
same, and the positions where these protruding pieces are installed
are two positions that are located on opposite sides in the radial
direction of the steering column or higher than that.
Preferably the steering column is die cast using a light metal
alloy, and this steering column is held between the support plate
sections so that the position of the steering column can be
adjusted with respect to these support plate sections, and the
steering column is formed such that it is integrated with the
protruding pieces.
In yet another form of the steering column support apparatus of the
present invention, alternatively or additionally, a sliding layer
made of a low friction material is provided in at least one side in
the width direction of the engagement section between the portion
on both sides in width direction of the locking capsule and the
portion of the bracket on the vehicle side that is located on both
sides in the width direction of the locking hole.
The sliding layer can be formed by using a sliding plate that is
separate from the bracket on the vehicle side and the locking
capsule. In this case, this sliding plate comprises a flat
installation plate section that is placed on the portion of the
bracket on the vehicle side that surrounds the locking hole, and a
hanging plate section that is formed by bending downward from the
inside edge of the installation plate section, and this hanging
plate section fits inside the locking hole and covers at least the
inside edges on the left and right sides of the locking hole, and
the installation plate section is held between the bottom surface
of the flange section of the locking capsule and the top surface of
the bracket on the vehicle side in the portion that surrounds the
locking hole.
In this construction, preferably there is a bottom plate section
that is bent from the edge on the bottom end of the hanging plate
section in the same direction as the installation plate section,
and the portion of the bracket on the vehicle side that surrounds
the locking hole is held between the top surface of this bottom
plate section and the bottom surface of the installation plate
section.
In the installation plate section of the sliding plate, it is
possible to form a plurality of small through holes in portions
that are aligned with the small through holes that are formed in
the flange section of the locking capsule, and with the
installation plate section held between the flange section and the
bracket on the vehicle side, connecting pins can be formed to span
between the small through holes of the locking capsule and small
through holes or small notch sections that are formed in the
bracket on the vehicle side.
In even yet another form, preferably the connecting strength of the
locking capsule and the bracket on the vehicle side with respect to
an impact load is asymmetrical on the left and right of the
steering column. More specifically, one of the methods below is
employed.
(1) The number of connecting pins on the left and right differs
from each other.
(2) The diameters of the connecting pins on the left and right
differ from each other.
(3) The position where the bracket on the column side is connected
and fastened to the locking capsule is shifted to either direction
in the width direction.
(4) Of the left and right inside edges of the locking hole, one of
the inside edges is parallel with the steering column, and the
other inside edge is inclined in a direction away from the one
inside edge going in toward the front.
(5) Of the portion of the top surface of bottom surface of the
bracket on the vehicle side that comes in contact with the flange
section of the locking capsule, a sliding layer made of a
low-friction material is provided only on the portion on one side
in the width direction of the locking hole.
In the steering column support apparatus of the present invention,
it is possible to alternatively use a member having the
construction below for the bracket on the column side. In other
words, in this alternative form, a pair of left and right bracket
elements is each formed by bending metal plate. Each bracket
element comprises an installation plate section that is formed on
the top end section, an inclined plate section that is bent from
the inside edge of the installation plate section to the outside in
the width direction such that the crossing angle with the
installation plate section is an acute angle, and is inclined in a
downward direction toward the outside in the width direction, and a
support plate section that hangs down from the edge of the bottom
end of the inclined plate section, and the pair of support plate
sections are for holding and supporting the portion fastened to the
steering column from both the left and right sides. These bracket
elements are arranged so that the support plate sections are
parallel with each other, and a plurality of locations in the
forward/backward direction are fastened to the locking capsule by
rod shaped members such as bolts and nuts, rivets or the like.
Effect of the Invention
The steering column support apparatus of the present invention
simplifies tuning for stabilizing the forward displacement of the
steering wheel during a secondary collision, and suppresses the
absolute value and variation of the break away load without strong
rubbing between the bottom surface of the bracket on the vehicle
side and the top surface of the bracket on the column side.
Moreover, as necessary, the steering column support apparatus can
prevent the steering wheel from dropping excessively after a
secondary collision.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view illustrating a first example of a
first embodiment of the present invention, and illustrates the
state as seen from the upper rear.
FIG. 2 is an end view of the construction in FIG. 1 with part
omitted, and illustrates the state as seen from the rear.
FIG. 3 is a top view of the construction in FIG. 1 with part
omitted, and illustrates the state as seen from above.
FIG. 4 is an enlarged cross-sectional view of section a-a in FIG.
3, and illustrates a first example of the construction of a
connecting section between a bracket on the vehicle side and a
bracket on the column side.
FIG. 5 is a cross-sectional view similar to FIG. 4, and illustrates
a second example of the construction of a connecting section
between a bracket on the vehicle side and a bracket on the column
side.
FIG. 6 is a cross-sectional view of section b-b for the first
example of the first example of the present invention.
FIG. 7 is a top view of the construction in FIG. 6 with part
omitted, and illustrates the state as seen from above.
FIG. 8 is a cross-sectional view of section b-b in FIG. 4 for
construction separate from the first embodiment of the present
invention.
FIG. 9 is an enlarged view of part d in FIG. 8.
FIG. 10 is an enlarged view of a portion of a second example of the
first embodiment which corresponds to part c in FIG. 6.
FIG. 11 is a view similar to FIG. 10, and illustrates a third
example of the first embodiment of the present invention.
FIG. 12 is a perspective view of the main section of a first
example of a second embodiment of the present invention which
corresponds to the center section in FIG. 1.
FIG. 13 is a side view of the main section shown in FIG. 12 as seen
from the side.
FIG. 14 is a drawing illustrating the state as seen from the right
in FIG. 13 with part omitted, and is a cross-sectional view of the
steering column and illustrates the connecting section between the
outer column and the inner column.
FIG. 15 is a top view of the main section shown in FIG. 14 as seen
from above with the bracket on the vehicle side omitted.
FIG. 16 is a perspective view of a main section of a first example
of a third embodiment of the present invention, which corresponds
to the center section in FIG. 1.
FIG. 17 is a side view illustrating the state in FIG. 16 as seen
from the side.
FIG. 18 is a top view illustrating the state in FIG. 16 as seen
from above.
FIG. 19 is an enlarged cross-sectional view of section e-e in FIG.
18.
FIG. 20 is a perspective view of a sliding plate that is used in
the first example of the third embodiment of the present invention,
and illustrates the state as seen from the lower rear after the
plate has been removed.
FIG. 21 is a drawing similar to FIG. 19, and illustrates a second
example of the third embodiment of the present invention.
FIG. 22 is a partial cross-sectional view illustrating a third
example of the third embodiment of the present invention, and
corresponds to the left end section in FIG. 21.
FIG. 23 is a drawing similar to FIG. 18, and illustrates a fourth
example of the third embodiment of the present invention.
FIG. 24 is a partial top view illustrating a fifth example of the
third embodiment of the present invention, and corresponds to the
top side section in FIG. 18.
FIG. 25 is a cross-sectional view of section f-f in FIG. 31, and
illustrates an example of construction that considers reducing the
break away load.
FIG. 26 is a top view of only the bracket on the column side that
has been removed, and illustrates the state in FIG. 25 as seen from
above.
FIGS. 27A to 27E illustrate five examples of construction in a
fourth embodiment of the present invention for reducing the break
away load, where FIGS. 27A to 27C are top views of the locking
capsule, and FIGS. 27D and 27E are top views of the bracket on the
vehicle side.
FIG. 28 is a perspective view illustrating an example of a fifth
embodiment of the present invention, and illustrates the state as
seen from the upper rear.
FIG. 29 is a side view illustrating the state in FIG. 28 as seen
from the side.
FIG. 30 is an end view of the state in FIG. 28 as seen from the
right.
FIG. 31 is a partial cross-sectional view illustrating an example
of a conventionally known steering apparatus.
FIG. 32 is a top view of an example of a conventional steering
column support apparatus, and illustrates the normal state.
FIG. 33 is a side view of the same state of the apparatus
illustrated in FIG. 32.
FIG. 34 is side view of an example of a conventional steering
column support apparatus, and illustrates the state wherein the
steering column as displaced in the forward direction due to a
secondary collision.
FIG. 35 is a cross-sectional view illustrating an example of
conventional construction, and is related to a virtual plane that
exists in a direction orthogonal to the center axis of the steering
column.
FIG. 36 is a perspective view of the construction illustrated in
FIG. 35, and illustrates the state before the bracket on the
vehicle side and the bracket on the column side are connected.
FIG. 37 is a perspective view of the construction illustrated in
FIG. 36 with the steering column omitted and the connecting pins
depicted.
BEST MODES FOR CARRYING OUT THE INVENTION
First Example of First Embodiment
FIG. 1 to FIG. 7 illustrate a first embodiment of the present
invention. This embodiment illustrates the case of applying the
present invention to a tilting and telescopic type steering
apparatus that comprises both a tilting mechanism for adjusting the
up/down position of the steering wheel 1 and a telescopic mechanism
for adjusting the forward/backward position of the steering wheel 1
(see FIG. 31).
In order to construct a telescopic mechanism, a telescopic shaped
steering column 6c that can expand or contract along the entire
length by fitting the rear section of an inner column 23 on the
front side inside the front section of an outer column 24 on the
rear side is used. A steering shaft 5b is supported in the inner
diameter side of this steering column 6c such that it can rotate
freely, however, this steering shaft 5b as well is constructed such
that by a male spline section that is formed on the rear section of
a circular rod shaped inner shaft that is located on the front side
engaging with a female spline section that is formed on the front
section of a cylindrical shaped outer shaft 25 that is located on
the rear side, the steering shaft 5b can transmit torque as well as
expand and contract. With the rear end section of the outer shaft
25 protruding further toward the rear than the opening on the rear
end of the outer column 24, the outer shaft 25 is supported on the
inner diameter side of the outer column 24 by a bearing such as a
single-row deep groove ball bearing 26 or the like that is capable
of supporting both a radial load and thrust load such that only the
rotation is possible. A steering wheel 1 is supported by and
fastened to the rear end section of the outer shaft 25. When
adjusting the forward/backward position of this steering wheel 1,
the outer shaft 25 and the outer column 24 displace in the forward
or backward direction, and the steering shaft 5b and steering
column 6c expand or contract.
A housing 10a for housing a reduction gear and the like of an
electric power steering apparatus is connected and fastened to the
front end section of the inner column 23 of this steering column
6c. An electric motor 27, which is the auxiliary power source for
the electric power steering apparatus, and a controller 28 for
controlling the flow of electricity to this electric motor 27 are
fastened to and supported by the top surface of the housing 10a. In
order to construct the tilting mechanism, the housing 10a is
supported by the vehicle body such that it can swivel around a
horizontal shaft. In order for this, a support cylinder 29 is
provided in the left/right direction on the upper front end of the
housing 10a, and the front end section of the steering column 6c is
supported by the vehicle body by a horizontal shaft such as a bolt
that is inserted through a center hole 30 in the support cylinder
29 such that the rear section of this steering column 6c can swivel
in the raising or lowering direction.
The inner diameter of the front half of the outer column 24 of the
middle section or rear section of the steering column 6c can expand
or contract elastically. In order for this, a slit 31 is formed in
the axial direction on the bottom surface of the outer column 24.
The front end section of this slit 31 opens up to a through hole 59
in the circumferential direction (see FIG. 17) that is formed on
the edge of the front end of the outer column 24 or in the portion
near the front end section of the outer column 24 except the top
end section. A pair of thick plate-shaped supported plate sections
32 is located in the portion between both sides in the width
direction of the slit 31. These supported plate sections 32
displace together with the outer column 24 when adjusting the
position of the steering wheel 1, and function as support brackets
on the displacement side.
In the case of this example, the supported plate sections 32 are
supported by a bracket 33 on the column side such that adjustment
of the up/down position and forward/backward position is possible.
This bracket 33 on the column side is normally supported by the
vehicle body, however, during a collision accident, breaks away in
the forward direction due to the impact of a secondary collision,
which allows displacement in the forward direction of the outer
column 24. In order for this, the bracket 33 on the column side is
supported by a bracket 11a on the vehicle side such that it can
break away in the forward direction due to an impact load that is
applied during a secondary collision.
The adjustment section of the tilting mechanism and telescopic
mechanism is constructed by firmly holding the supported plate
sections 32 by a pair of left and right support plate sections 34
of the bracket 33 on the column side. Long holes 35 in the up/down
direction having a partial arc shape that are centered around the
horizontal shaft that supports the support cylinder 29 with respect
to the vehicle body are formed in these support plate sections 34,
and long holes 36 in the forward/backward direction that are long
in the axial direction of the outer column 24 are formed in the
supported plate sections 32. An adjustment rod 37 is inserted
through these long holes 35, 36. A head section 38 that is located
on the base end section (right end section in FIG. 2) of this
adjustment rod 37 engages with the long hole 35 in the up/down
direction that is formed in one of the support plate sections 34
(right support plate section in FIG. 2) to prevent rotation, and
only allows displacement along this long hole 35 in the up/down
direction. On the other hand, a cam apparatus 42 having a driving
cam 40 and a driven cam 41 is provided between the nut 39 that is
screwed onto the tip end section (left end section in FIG. 2) of
the adjustment rod 37 and the outside surface of the other support
plate section 34 (left support plate section in FIG. 2). Of these
cams, the driving cam 40 can be rotated and driven by an adjustment
lever 43.
When adjusting the position of the steering wheel 1, the driving
cam 40 is rotated and driven by rotating the adjustment lever 43 in
a specified direction (downward), shortening the dimension in the
axial direction of the cam apparatus 42. This widens the space
between the inside opposing surfaces of the driven cam 41 and the
head section 38, and releases the holding force that the support
plate sections 34 on both sides apply to the supported plate
sections 32. At the same time, the inner diameter of the portion on
the front section of the outer column 24 in which the rear section
of the inner column 23 is fitted elastically expands, which lowers
the contact pressure that acts in the area of contact between the
inner circumferential surface on the front section of the outer
column 24 and the outer circumferential surface on the rear section
of the inner column 23. In this state, the up/down position and the
forward/backward position of the steering wheel 1 can be adjusted
within the range in which the adjustment rod 37 can be displaced
between the long holes 35 in the up/down direction and the long
holes 36 in the forward/backward direction.
After the steering wheel 1 has been moved to a desired position,
the dimension in the axial direction of the cam apparatus 42 is
expanded by rotating the adjustment lever 43 in the opposite
direction (upward) of the specified direction above. As a result,
the space between opposing inside surfaces of the driven cam 41 and
the head section 38 is shortened, and the supported plate sections
32 are held firmly on both sides by the support plate sections 34.
At the same time, the inner diameter of the portion on the front
section of the outer column 24 in which the rear section of the
inner column 23 is fitted elastically contracts, and the contact
pressure acting at the area of contact between the inner
circumferential surface of the front section of the outer column 24
and the outer circumferential surface of the rear section of the
inner column 23 increases. In this state, the steering wheel 1 is
held in the adjusted up/down and forward/backward positions.
In this embodiment, in order to increase the supporting force for
holding the steering wheel 1 in the adjusted position, friction
plate units 44 are held between the inside surfaces of the support
plate sections 34 and the outside surfaces of the supported plate
sections 32. These friction plate units 44 are formed by
alternately overlapping one or a plurality of first friction plates
having long holes that are aligned with the long holes 35 in the
up/down direction, and one or a plurality of second friction plates
having long holes that are aligned with the long holes 36 in the
forward/backward direction. The detailed construction and function
of this kind of friction plate unit 47 is known (refer to
JP2007-69821(A) and JP2008-100597(A)), and is not related to the
gist of the present invention, so a detailed drawing and
explanation are omitted.
Furthermore, the bracket 33 on the column side breaks away in the
forward direction with respect to the bracket 11a on the vehicle
side due to the impact load of a secondary collision, however, is
supported so that it cannot drop downward even as the secondary
collision advances. The bracket 11a on the vehicle side is fastened
to and supported by the vehicle body and does not displace in the
forward direction during a secondary collision, and this bracket is
formed by the punching and bending of metal plate, such as steel
plate, having sufficient strength and rigidity. The bracket 11a on
the vehicle side is a flat plate, however, the rigidity is improved
by bending the edges on both sides and the edges on the front and
rear downward. A locking hole (locking notch) 45 that extends in
the axial direction of the steering column 6c and that is open on
the edge of the front end is formed in the center section in the
width direction of the bracket 11a on the vehicle side, and a pair
of installation holes 46 is formed in the rear section of the
bracket 11a on the vehicle side such that the installation holes 46
are on both the left and right sides of the locking hole 45. The
locking hole 45 is covered by a locking capsule 47, and is formed
so as to extend near the rear end section of the bracket 11a on the
vehicle side. This bracket 11a on the vehicle side is supported by
and fastened to the vehicle body by bolts or studs that are
inserted through the installation holes 46. In this example, the
locking hole 45 is formed as a notch that is open on the front
edge, however, the shape of the locking hole 45 is not limited to
this, and construction is also possible in which the locking hole
is formed as a closed hole that extends in the axial direction of
the steering column being closed on the front edge, and that is
capable of preventing the locking capsule 47 from dropping from the
bracket 11a on the vehicle side.
The bracket 33 on the column side is connect to the bracket 11a on
the vehicle side by way of the locking capsule 47 so as to be able
to break away in the forward direction during a secondary
collision. In this example, the construction illustrated in FIG. 4
is used as the locking capsule 47. This locking capsule 47 is
formed by plastic working such as forging of an iron alloy such as
mild steel, die casting a light alloy such as an aluminum alloy or
magnesium alloy, or injection molding of a high strength high
functional polymer such as polyacetal. The width dimension in the
left and right direction and the length dimension in the forward
and backward direction are larger in the upper half section (top
side section) than in the lower half section (base section), and a
flange section 48 that protrudes toward both sides and toward the
rear is formed on the upper half section of the locking capsule 47
on the surfaces of both the left and right sides and the rear.
When this kind of locking capsule 47 is locked in (fitted inside)
the locking hole 45 that is formed in the bracket 11a on the
vehicle side, the locking capsule 47 is supported by the bracket
11a on the vehicle side such that it can break away in the forward
direction due to an impact load that is applied during a secondary
collision. In order for this, small through holes 49a, 49b are
formed in a plurality of aligned locations (eight locations in the
example in the figure) in the flange section 48 and in the bracket
11a on the vehicle side in the edges around the locking hole 45.
Connecting pins 50 span between these small through holes 49a, 49b.
Instead of the small through holes 49b that are formed in the
bracket 11a on the vehicle side, it is possible to form small notch
sections that are open toward the inside of the locking hole 45. In
the present invention, construction using connecting pins is
preferable, however, it is possible to omit these connecting pins
50 and employ construction wherein the locking capsule 47 is
pressure fitted inside the locking hole 45.
These locking pins 50 can be formed by aligning the small through
holes 49a, 49b and injecting synthetic resin into these small
through holes 49a, 49b by injection molding and then allowing the
synthetic resin to solidify, or pins can be formed into solid
cylindrical shapes beforehand using synthetic resin or a light
metal alloy, then with a large force in the axial direction,
pressure fitting the pins into these small through holes 49a, 49b.
In either case, part of the synthetic resin material or light metal
alloy material of these connecting pins enters into the space
between the top and bottom surfaces of the bracket 11a on the
vehicle side and the opposing surfaces to these top and bottom
surfaces, which are the bottom surface of the flange section 48 and
the top surface of the bracket 33 on the column side, and this
eliminates vibration in the installation section between the
bracket 11a on the vehicle side and the bracket 22 on the column
side. In FIG. 4, for clarity, the height of the space that is the
cause of this vibration is drawn larger than actual size.
This locking capsule 47 is connected and fastened to the bracket 33
on the column side by a plurality bolts 51 and nuts 52 (three in
the example in the figure) so that they do not separate regardless
of any impact load. More specifically, by inserting bolts 51 from
the bottom through the through holes that are formed in aligned
positions in the locking capsule 47 and bracket 33 on the column
side, and then screwing nuts 52 onto the portions on the tip end
sections (top end sections) of the bolts 51 that protrude from the
top surface of the locking capsule 47, and tightening the nuts 52,
the locking capsule 47a and the bracket 33 on the column side are
connected and fastened together. Therefore, during a secondary
collision, the impact load that is transmitted from the outer
column 24 to this bracket 33 on the column side is transmitted as
is to the locking capsule 47, and when the connecting pins 50
shear, the outer column 24 also displaces in the forward direction
in synchronization with the displacement in the forward direction
of the locking capsule 47. FIG. 6 to FIG. 11 illustrate
construction wherein the locking capsule 47 and the bracket 33 on
the column side are connected and fastened using a plurality of
rivets 54 instead of the bolts 51 and the nuts 52. It is possible
to connect and fasten the locking capsule 47 and bracket 33 on the
column side using rivets 54 or using bolts 51 and nuts 52, and
which is used is not related to the scope of the present
invention.
On the other hand, the bracket 33 on the column side is made by
using a press to punch and bend metal plate having sufficient
strength and rigidity such as carbon steel plate. The shape of the
bracket 33 on the column side is a U shape that is formed by
connecting a pair of left and right support plate sections 34 with
a top plate section 55. The portions of the bracket 11a on the
vehicle side on both the left and right sides of the locking hole
45 are held between the bottom surface of the flange section 48
that is formed on the upper half section of the locking capsule 47
and the top surface of the top plate section 55, which is a support
plate on the underneath side. In this example, the back end section
(rear end section) of the locking hole 45 and the rear end section
of the lower half of the locking capsule 47 are inclined in a
direction such that the width dimension becomes smaller going
toward the rear, such that the break away load that causes the
locking capsule 47 to break away from the locking hole during a
secondary collision is lowered.
Particularly, the bracket 33 on the column side in the construction
of this example is such that the front end section of the top plate
section 55 extends further toward the front than the edges on the
front ends of the support plate sections 34, forming an extending
section 57 having a cantilever shape. A convex curved surface 58
having an arc shaped cross section (partial cylindrical surface) is
formed on the portion near the front end of the top surface of this
extending section 57. The arc that represents the cross-sectional
shape of this convex curved surface 58 and a straight line that
represents the cross-sectional shape of the portion from the middle
section to near the base end on the top surface of the extending
surface 57 smoothly connect with each other. In other words, this
straight line is continuous in the tangent direction of the arc.
Therefore, the convex curved surface 58 is an inclined surface that
is inclined in a downward direction going toward the edge on the
front end. This kind of convex curved surface 58 can be formed by a
cutting process to remove the excess portion, or more preferably,
is formed by plastic working using a press. This is because in
plastic working the convex curved surface 58, which is a smooth
surface, can be processed efficiently.
Because of its ultrathin construction, it is omitted in the
figures, however, a low-friction material layer is located in the
area of contact between the top surface of the top plate section 55
and the bottom surface of the portion of the bracket 11a on the
vehicle side on both the left an right sides of the locking hole
45. This low-friction material layer could be a coating layer made
of synthetic resin having a low friction coefficient such as a
polyamide resin, polytetrafluoroethylene resin, and the like, or a
metal plated layer having self lubrication such as copper or copper
alloy or could be a thin plate (sliding plate) made of this kind of
resin or metal.
With the construction of this example, constructed as described
above, strong local rubbing between the top surface of the top
plate section 55 and the bottom surface of the portion of the
bracket 11a on the vehicle side on both the left and right sides of
the locking hole 45 during a secondary collision is prevented and
the absolute value of the break away load and variations in the
load are kept low. The reason for this is explained below by using
a comparison with the construction illustrated in FIG. 8 and FIG. 9
that does not use the construction of this example.
During a secondary collision, the impact load that is transmitted
from the steering wheel 1 to the steering column 6c by way of the
steering shaft 5b is inputted to the bracket 33 on the column side
by way of the supported plate sections 32, which are a bracket on
the displacement side that is formed in part of the steering
column, and the adjustment rod 37 that is inserted though the long
holes 35 in the up/down direction of the support plate sections 34
of the bracket 33 on the column side. In other words, during a
secondary collision, this adjustment rod 37 strongly presses the
front inside edges of the long holes 35 in the up/down direction.
As a result, a moment in the clockwise direction in FIG. 6 and FIG.
8 is suddenly applied to the bracket 33 on the column side with the
adjustment rod 37 as the point where the force acts (input section)
and the connecting section between the locking capsule 47 and the
bracket 33 on the column side as the fulcrum.
In a case where the construction of this example is not used, the
top surface of the top plate section 55a essentially comes in
contact with the bottom surface of the bracket 11a on the vehicle
side (the space in FIG. 4 is exaggerated), so when this kind of
sudden moment is applied, in the portion enclosed in the dot-dash
line a in FIG. 9, the front edge section on the top surface of the
top plate 55a of the bracket 33a on the column side is strongly
pressed against the bottom surface of the bracket 11a on the
vehicle side. Therefore, during a secondary collision, the front
edge section on the top surface of the top plate section 55a is
strongly pressed against and bites into the bottom surface of the
bracket 11a on the vehicle side. As a result, a large friction
force acts in the portion. The front edge section on the top
surface of the top plate 55a is pointed, making it easy for that
edge to bite into the opposing surface. Therefore, the load
required in order to come out from the locking hole 45 that is
formed in the bracket 11a on the vehicle side becomes comparatively
large.
On the other hand, in the construction of this example, a convex
curved surface 58 is formed on the front edge section on the top
surface of the extending section 57, so no pointed (cross section
having an extremely small radius of curvature) edge comes in
contact with the bottom surface of the bracket 11a on the vehicle
side. Contact is made from the base end section (rear end section)
to the middle section of the convex curved surface 58, so the
surface area of contact is comparatively large. The extending
section 57 is a cantilever shape with the tip end (front end) that
comes in contact with the bottom surface of the bracket 11a on the
vehicle side being the free end, so when the bracket 33 on the
column side is displaced by a moment, the extending section 57 is
such that the tip elastically deforms in the direction going away
from the bottom surface of the bracket 11a on the vehicle side. As
a result, it is possible to keep the contact pressure at the area
of contact between the bottom surface of the bracket 11a on the
vehicle side and the top surface of the top plate section 55 low,
and it becomes difficult for the front edge on the top surface of
the extending section 57 to bite into the bottom surface of the
bracket 11a on the vehicle side. In the case of this example, there
is a low-friction material layer at the area of contact between the
top surface of the extending section 57 and the bottom surface of
the bracket 11a on the vehicle side, so it is even more difficult
for the convex curved surface 58 to bite into the bottom surface of
the bracket 11a on the vehicle side. With the construction of this
example having these multiple effects, it is possible to keep the
absolute value of the break away load and any variation in the load
during a secondary collision even lower, and thus design for
effectively protecting the driver becomes easier.
In the steering column support apparatus of this example, having
construction as described above, by having the bracket 11a on the
vehicle side and the locking capsule 47 engage at only the center
section in the width direction of the bracket 11a on the vehicle
side, it is possible to simplify tuning for stabilizing the forward
displacement of the steering wheel 1 during a secondary collision.
A single locking capsule 47 is placed in a portion directly above
the outer column 24 in this way, so during a secondary collision,
the impact load that is transmitted to the locking capsule 47 from
the steering wheel 1 by way of the outer shaft 25 and outer column
24 is applied nearly uniformly to locking pins 50, which are the
connecting members that connect the locking capsule 47 and the
bracket 11a on the vehicle side, and essentially acts on the center
section of the locking capsule in the axial direction of the outer
column 24. When a force is applied that causes this single locking
capsule 47 to come out in the forward direction from the locking
hole 45, the locking pins 50 that connect this locking capsule 47
and the bracket 11a on the vehicle side essentially shear
simultaneously. As a result, displacement in the forward direction
of the outer column 24 that is connected to the locking capsule 47
by way of the bracket 33 on the column side can be performed stably
with no excessive inclination of the center axis.
Particularly, in the case of this example, presuming this kind of
construction, a method of suppressing a rise in contact pressure is
further provided, and by suppressing a rise in contact pressure at
the area of contact between the front edge sections on the top
surface of the support plate on the underneath side, the absolute
value of the break away load during a secondary collision and any
variation in the load is suppressed. In other words, in
construction where the top surface of the top plate section 55 of
the bracket 33 on the column side comes in contact with the bottom
surface of the bracket 11a on the vehicle side, when it is
necessary to maintain strength and rigidity of the members, the
members are made of a ferrous alloy plate (typically, carbon steel
plate). As a result, when a moment is applied during a secondary
collision, the bottom surface of the bracket 11a on the vehicle
side and the front edge on the top surface of the top plate section
55 of the bracket 33 on the column side come in contact over a
small surface area, the contact pressure that acts at the area of
contact becomes high, so it becomes easy for the front edge of the
top surface of the top plate section 55 to bite into the bottom
surface of the bracket 11a on the vehicle side, and it becomes easy
for the absolute value of the break away load and any variations in
the load during a secondary collision to become large. On the other
hand, in this example, even when the bracket 33 on the column side
displaces due to a moment that is applied during a secondary
collision, there is no contact between the front edge on the top
surface of the underneath support plate that has a pointed shape
and the bottom surface of the bracket 11a on the vehicle side, but
comes in contact with a portion closer to the base end than the
edge on the front end comes in contact and has a comparatively
large surface area. Therefore, it is possible to keep the contact
pressure at the area of contact low, it becomes difficult for the
front edge on the top surface of the top plate section 55 to bite
into the bottom surface of the bracket 1a on the vehicle side, and
the absolute value and variation of the break away load during a
secondary collision is kept low.
Moreover, at the same time, in this example, by forming an
extending section 57 that protrudes further toward the front than
the edges on the front end of the flange section 48, the front edge
of the top surface of the top plate section 55 of the bracket 33 on
the column side comes in contact with the bottom surface of the
bracket 11a on the vehicle side, however the contact pressure at
the area of contact is kept low. In other words, in this case, when
the bracket 33 on the column side displaces due to a moment that is
applied during a secondary collision, and the front edge on the top
surface of the top plate section 55 comes in contact with the
bottom surface of the bracket 11a on the vehicle side, the
extending section 57 elastically deforms downward. This extending
section is a cantilever with the front edge side being the free
end, and because the rigidity of this front edge side is low, the
contact pressure at the area of contact is kept low. Therefore, it
is possible to keep the contact pressure at the area of contact
low, it becomes difficult for the front edge of the top surface of
the top plate section 55 to bite into the bottom surface of the
bracket 11a on the vehicle side, and the absolute value and
variations in the break away load can be kept low.
In this example, an inclined surface is formed on the portion near
the front end on the top surface of the extending section 57, and
by combining the two features described above, an effect of being
able to keep the absolute value and variations of the break away
load is redundantly obtained, however, a sufficient effect is
obtained even if only one of these is used.
Furthermore, in this example, the length L.sub.45 in the
forward/backward direction of the locking hole 45, in which the
locking capsule 47 that displaces in the forward direction together
with the outer column 6c during a secondary collision, is
sufficiently greater than the length L.sub.47 in the same direction
of the locking capsule 47 (L.sub.45>>L.sub.47). Particularly,
in this example, the length L.sub.45 of the locking hole is 2 times
the length L.sub.47 of the locking capsule 47 or greater
(L.sub.45.gtoreq.L.sub.47). During a secondary collision, when the
locking capsule 47 has displaced all the way forward together with
the outer column 24, in other words, even when the locking capsule
can no longer displace in the forward direction due to an impact
load that was applied from the steering wheel, the portion of at
least the rear end section of the flange section 48 of the locking
capsule 47 that can support the weight of the steering column 6c
and the bracket 33 on the column side does not come out all the way
from the locking hole 45. That is, even when the dimension in
forward/backward direction of the bracket 11a on the vehicle side
is limited, the length (collapse stroke) that the locking capsule
47 displaces in the forward direction during a secondary collision
is maintained, and even when the secondary collision advances, the
rear end section of the flange 48 that is formed on both sides in
the width direction of the upper half of the locking capsule 47 is
positioned on the top side of the front end section of the bracket
11a on the vehicle side, and can prevent the locking capsule 47
from dropping. However, when the dimension in the forward/backward
direction of the bracket 11a on the vehicle side can be
sufficiently maintained, as described above, it is possible to
prevent the locking capsule 47 from dropping from the bracket 11a
on the vehicle side, and at the same time increase the rigidity of
the front section of the bracket 11a on the vehicle side by forming
the locking hole to be a closed hole with no opening on the edge of
the front end. With this kind of construction, the steering wheel
is prevented from dropping excessively, and even after a collision
accident, the steering wheel can be easily operated; for example,
when a vehicle that was in an accident can move under its own
power, it is possible to easily drive the vehicle that was in the
accident from the site of the accident to the side of the road.
Furthermore, a pair of left and right protruding sections that
protrude further outward in the width direction than the left and
right outside surfaces of the bracket 33 on the column side are
formed in part of the bracket 33 on the column side, and part of
the edges on the top end of these protrusions can be such that they
closely face part of the bottom surface of the bracket 11a on the
vehicle side. As a result, when a moment around the axial direction
is applied to the bracket 33 on the column side, and the bracket 33
on the column side inclines a little, part of the edge on the top
end of one of the protruding sections comes in contact with the
part of the bottom surface of the bracket 11a on the vehicle side,
making it possible to prevent the bracket 33 on the column side
from inclining more than this. With this kind of construction, even
though a moment is applied to the bracket 33 on the column side,
the amount of relative displacement between the bracket 33 on the
column side and the bracket 11a on the vehicle side can be kept to
a small amount, and it is possible to prevent a force from being
applied to the bracket 33 on the column side and the locking
capsule 47 that is capable of damaging these members.
Moreover, in this example, together with providing a tilt and
telescopic mechanism, friction plate units 44 are provided in order
to increase the holding force for holding the steering wheel 1 in
an adjusted position. Providing the tilt and telescopic mechanism
and the friction plate unit 44, because of accumulation of
manufacturing errors, easily become a cause for variation in the
break away load during a secondary collision, however, in this
example, through the engagement of the single locking capsule 47
and bracket 11a on the vehicle side it is possible to suppress this
kind of variation in break away load. As a result, it is possible
to perform proper tuning for lessening the impact applied to the
body of the driver that collides with the steering wheel 1 during a
secondary collision, making it possible to more completely protect
the driver.
In the steering column support apparatus of the present invention,
instead of the locking capsule 47 illustrated in FIG. 4, it is also
possible to employ the locking capsule 47a having the construction
illustrated in FIG. 5. The locking capsule 47 illustrated in FIG. 4
has a simple shape, and in addition to suppressing manufacturing
costs, the assembly height of the portion where the locking capsule
is installed is kept low, so is advantageous from the aspect of
being capable of making the steering column support apparatus more
compact and lightweight, and stabilizing the break away load of the
engagement section between the bracket 11a on the vehicle side and
the locking capsule 47 by shortening the distance between the
center axis of the outer column 24, which is the position where the
impact load acts, and the engagement section (suppresses torsion
due to this length becoming long).
However, the construction illustrated in FIG. 5 is advantageous
from the aspect of simplifying injection molding of the connecting
pins 50. In other words, in the case of the construction
illustrated in FIG. 4, when performing injection molding of the
connecting pins 50, it is necessary to perform injection molding
with the bracket 11a on the vehicle side, the locking capsule 47
and the bracket 33 on the column side connected by the bolts 51 and
nuts 52, however, in the case of the construction illustrated in
FIG. 5, only the bracket 11a and the locking capsule 47a need to be
set in the die for performing injection molding of the connecting
pins 50, so the die can easily be made more compact. In other
words, this locking capsule 47a has locking grooves 53 that are
formed on the surface of the left and right sides, and the edges on
both sides of the locking hole 45 of the bracket 11a on the vehicle
side engage with these locking grooves 53. Therefore, it is
possible to connect and fasten together the locking capsule 47a and
the bracket 33 on the column side with the bolts 51 and nuts 52
after the bracket 11a on the vehicle side and the locking capsule
47a have been connected by the connecting pins 50.
In the locking capsule 47a having the construction illustrated in
FIG. 5, as in the conventional construction illustrated in FIGS. 35
to 37, as long as the locking capsule 47a is made of a light alloy
or a synthetic resin, it becomes difficult for the top surface of
the bottom plate section 56 that defines the bottom side of the
locking groove 53 of the locking capsule 47a to bite into the
bottom surface of the bracket 11a on the vehicle side, so the
possibility that the absolute value and variation of the break away
load will become large is low. However, in this case as well,
depending on the conditions, there is a possibility that due to
being affected by the moment described above, the absolute value
and variation of the break away load cannot always be kept
sufficiently low. Moreover, in the case where for reasons such as
maintaining strength and rigidity, the locking capsule 47a is made
of a ferrous alloy, there is a possibility for the same reason that
the absolute value or variation of the break away load could become
large. In other words, there is a possibility that the front edge
of the top surface of the bottom plate section 56 of the locking
capsule 47a will come in strong contact with the bottom surface of
the bracket 11a on the vehicle side due to the moment described
above, causing the absolute value or variation of break away load
to increase. In this case, the bottom plate section 56 corresponds
to the underneath support plate and it is possible to provide a way
to suppress a rise in contact pressure by: (1) forming an inclined
surface on the portion near the front end of the top surface of
this bottom plate section that is inclined downward going toward
the front edge of the bottom plate section 56; (2) providing an
extending section on the front end section of the bottom plate
section 56 that protrudes further toward the front than the edge on
the front end of the flange section 48; or (3) forming an inclined
surface on the portion near the front end on the top surface of the
extending section of the bottom plate section 56 that is inclined
downward going toward the edge on the front end of the extending
section.
Second Example of First Embodiment
FIG. 10 illustrates a second example of the first embodiment of the
present invention. In the case of this example, a convex curved
surface 58a is formed on the top surface of the front end section
of the top plate section 55b of the bracket 33 on the column side,
and there is no extending section 57 such as in the first example
of the first embodiment. In the construction of this example,
compared with the case of the first example, the effect of
stabilizing and keeping the break away load low during a secondary
collision is somewhat low, however, when compared with the
construction illustrated in FIG. 8 and FIG. 9, can stabilize and
keep this break away load low. The construction and functions of
other parts are the same as in the first embodiment, so drawings
and explanations of identical parts are omitted.
Third Example of First Embodiment
FIG. 11 illustrates a third example of the first embodiment of the
present invention. In this example, an extending section 57a is
provided on the front end section of the top plate section 55c of
the bracket 33 on the vehicle side, however, there is no convex
curved surface 58 as in the first example of the first embodiment.
In the construction of this example, compared with the case of the
first example, the effect of stabilizing and keeping the break away
load low during a secondary collision is somewhat low, however,
when compared with the construction illustrated in FIG. 8 and FIG.
9, can stabilize and keep this break away load low. The
construction and functions of other parts are the same as in the
first embodiment, so drawings and explanations of identical parts
are omitted.
Embodiment 2
FIG. 12 to FIG. 15 illustrate an example of a second embodiment of
the present invention that can be alternatively applied to or
additionally added to the first embodiment of the present
invention. The basic construction and function are the same as the
construction of the first embodiment, so drawings and explanations
of identical parts are either omitted or simplified, such that the
explanation below centers on the features of this example. As can
clearly be seen from FIG. 12 to FIG. 15, this example is at least
applied to construction in which there is no friction plate unit 44
for increasing the holding force of keeping the steering wheel in
the adjusted position.
In the case of the steering column support apparatus of this
example, a pair of protruding pieces 60 are fixed in the middle
section in the circumferential direction of the outer column 24a of
the steering column 6d in the portion further toward the rear side
than the pair of support plate sections 34a of the bracket 33 on
the column side. The outer column 24a is formed as a single member
by die casting using a light alloy metal such as aluminum alloy or
magnesium alloy, and the protruding pieces 60 are formed at two
locations on opposite sides in the radial direction of the surfaces
on the left and right sides of the outer column 24a such that they
protrude toward the left and right sides from portions having the
same height and position in the axial direction. The edges on the
front sides of the protruding pieces closely face portions of the
edges on the rear sides of the support plate sections 34a further
toward the top side than the adjustment rod 37.
During normal operation, as much space as possible is provided
between the edges on the front sides of the protruding pieces 60
and the edges on the rear sides of the support plate sections 34a
so that adjustment of the up/down position of the steering wheel 1
is possible. In other words, even when the steering column 6d is
pivoted around the horizontal shaft that is inserted through the
center hole 30 of the support cylinder 29 (see FIG. 1) in order to
perform up/down adjustment of the steering wheel 1, there is enough
space such that the edges on the front sides of the protruding
pieces 60 do not rub against and interfere with the edges on the
rear sides of the support plate sections 34a. However, the edges on
the front sides of the protruding pieces 60 are brought as close as
possible to the edges on the rear sides of the support plate
sections 34a as long as interference between these edges can be
prevented. When a secondary collision occurs, the adjustment rod 37
displaces to the rear end section of the long holes 36 in the
forward/backward direction illustrated in FIG. 1, and further
presses against the rear end sections of these long holes 36 in the
forward/backward direction, so there is a possibility that the
adjustment rod 37 will strongly press against the inside edges on
the front side of the long holes 35 in the up/down direction that
are formed in the support plate sections 34a, however, construction
is such that before that happens, the edges on the front sides of
the protruding pieces 60 will come in contact with the edges on the
rear sides of the support plates 34a. In other words, during a
secondary collision, the impact load that is transmitted from the
outer column 24a of the steering column 6d to the bracket 33d on
the column side is transmitted by way of the contact section
between the protruding pieces 60 and the edges on the rear sides of
the support plate sections 34a without going though the adjustment
rod 37.
With this example that uses this kind of construction, the absolute
value or variation of the break away load is kept low by preventing
the edge section on the front end of the top surface of the top
plate section 55d from coming into strong local rubbing with the
bottom surface of the portion of the bracket 11a on the vehicle
side on both the left and right sides of the locking hole 45. In
other words, the distance from the area of contact between the
edges on the front sides of the protruding pieces 60 an the edges
on the rear sides of the support plate sections 34a to the
engagement section between the locking hole 45 that is formed in
the bracket 11a on the vehicle side and the locking capsule 47 that
is fastened to the top surface of the top plate section 55d of the
bracket 33d on the column side is sufficiently shorter than the
distance from the adjustment rod 37 to this engagement section. The
distance from the input section (point where the force is applied)
of the moment to the engagement section, which is the fulcrum, is
related to keeping the force that is applied in a twisting
direction to this engagement section low. Therefore, it is possible
to keep the absolute value or variation of the break away load low
by reducing the friction force acting on this engagement
section.
The case was explained of applying the steering column support
apparatus of this example to a tilting and telescopic type steering
apparatus, however, from the aspect of stabilizing the function and
effect described above, applying this example to construction
having only a tilt mechanism, or in other words, construction that
does not have a telescopic mechanism is preferred. At least, in the
case of construction such as in the case of the first embodiment
illustrated in FIGS. 1 to 3 where in a friction plate unit 44 is
assembled for increasing the holding force for keeping the steering
wheel in an adjusted position, or in the case of a so-called
positive type telescopic mechanism that uses a gear (rack) type
position fixing construction, as a result of making the holding
force greater than the impact load that is applied during a
secondary collision, there is a possibility that the position of
the steering wheel during this secondary collision will not
displace to the very front adjustable position. In the case of a
steering columns support apparatus having this kind of positive
type telescopic mechanism, the outer surface on the front side of
the adjustment rod 37 becomes the force input section before the
edges on the front ends of the protruding pieces 60 and the edges
of the rear ends of the support plate sections 34a of the brackets
33d on the column side come in contact, so the possibility that the
inside edges on the front sides of the long holes 35 in the up/down
direction that are formed in the portions toward bottom of the
support plate sections 34a of the bracket 33d on the column side
will be pressed strongly in forward direction becomes high. Because
of this reason, applying this example to a steering apparatus
having a positive type telescopic mechanism is not preferred.
Even in the case of applying this example to a steering apparatus
having only a tilt mechanism, in order to obtain the function and
effect of the present invention, it is necessary that the edges on
the front ends of the protruding pieces 60 come in contact with the
edges on the rear ends of the support plate sections 34a of the
bracket 33d on the column side before the outer surface of the
adjustment rod 37 comes in contact with the inside edges on the
front sides of the long holes in the up/down direction that are
formed in the support plate sections 34a of the bracket 33d on the
column side. Therefore, regardless of the adjusted height position
of the steering wheel 1, it is necessary that the distance between
the outer surface of the adjustment rod 37 and the inside edges on
the front sides of the long holes 35 in the up/down direction be
greater than the distance between the edges on the front ends of
the protruding pieces 60 and the edges on the rear ends of the
support plate sections 34a. Therefore, preferably the distance
between the edges on the front sides of the protruding pieces 60
and the edges on the rear ends of the support plate sections 34 is
made to always be short by increasing the distance between the
outer surface on the front side of the adjustment rod 37 and the
inside edges on the front side of the long holes 35 in the up/down
direction by sufficiently maintaining the width dimensions in the
forward/backward direction of the long holes in the up/down
direction, or by making the edges on the rear ends of the support
plate sections 34a a convex curved arc shape that is centered
around a horizontal axis (the center axis of the bolt that is
inserted through the center hole 30 of the support cylinder 29)
that is the center of pivoting of the steering column 6d,
regardless of the adjusted height position of the steering wheel 1.
However, the present invention can be applied even in the case of a
steering apparatus having only a telescopic mechanism as long as
there is no positive type construction such as described above, and
as long as construction is such that a rod shaped member such as
the adjustment rod 37 be located underneath the steering column
6d.
Furthermore, in this example, preferably the pair of left and right
protruding pieces 60 are at a position having the same height so
that there is no extra force applied to the bracket 33d on the
column side in a twisting direction. In the example in the figure,
the pair of protruding pieces 60 is located at two positions on
opposite sides in the radial direction where the dimension in the
width direction of the outer column 24a is the greatest, and the
amount that these protruding pieces 60 protrude from the outer
surface of the outer column 24 is kept small. However, by making
the protruding amount large, the position of the pair of left and
right protruding pieces can be closer to the bracket 11a on the
vehicle side on the top side. The closer the position of these
protruding pieces is to the bracket 11a on the vehicle side, or in
other words, the higher they are, or most preferably, when they are
located on the top end section of the outer column 24a, it is
possible to keep the force applied to the engagement section
between the locking hole 45 that is formed in the bracket 11a on
the vehicle side and the locking capsule 47 that is fastened to the
top surface of the top plate section 55d of the bracket 33d on the
column side in a twisting direction small.
First Example of Third Embodiment
FIG. 16 to FIG. 20 illustrate a first example of a third embodiment
of the present invention. The feature of this example is being able
to smoothly separate (break away) the locking capsule 47 from the
bracket 11b on the vehicle side by devising the construction of the
connection between the bracket 11b on the vehicle side and the
locking capsule 47 that is connected and fastened to the bracket 33
on the column side. The construction and functions of the other
parts are the same as in the construction of the first embodiment,
so drawings and explanations of identical parts are omitted or
simplified such that the explanation below centers on the feature
of this example.
In this example, the locking capsule 47 is connected and fastened
to the top surface of the bracket 33 on the column side by
plurality of bolts 51a and nuts 52 (three in the example in the
figure). In this example, the head sections 61 of the bolts 51a are
flat disc shaped so as to suppress the assembly height of the
steering column. However, the bracket 33 on the column side and the
steering capsule 47 can be connected and fastened by rivets as
illustrated in FIG. 6 to FIG. 11.
In this example as well, the rear half section of the locking hole
(locking notch) 45a that is formed in the bracket 11b on the
vehicle side is a similar shape but a little larger than the lower
half section of the locking capsule 47. That is, the width
dimension of the locking hole 45a is a little larger than the width
dimension of the portion of the lower half section of the locking
capsule 47 when the forward/backward positions coincide in the
combined state illustrated in FIG. 16. The amount that the width
dimension of the locking hole 45a is larger than the width
dimension of the lower half section of the locking capsule is two
times the thickness dimension of the hanging plate section 63 of
the sliding plate 62 or greater.
The bracket 33 on the column side and the locking capsule 47 are
connected to the bracket 11b on the vehicle side by way of a
plurality of connecting pins 50. This sliding plate 62 is formed by
bending metal plate, having a smooth surface (small surface
roughness) and preferably having a low surface friction coefficient
and a certain amount of rigidity (does not have low rigidity such
as foil), into a flat U shape that is open toward the front and has
a L shaped cross-section. Preferably, metal plate such as steel
plate having a coating layer made of synthetic resin having low
friction such as polyamide resin or polytetrafluoroethylene resin
on the surface is used as this metal plate. In addition to this, it
is also possible to use hard metal plate that is anti corrosive
such as stainless spring steel plate, or metal plate having
lubricating properties such as phosphor copper bronze plate.
Furthermore, it is also possible to combine the locking capsule
made of synthetic resin or light metal alloy and the sliding plate
made of synthetic resin.
In either case, the sliding plate 62 comprises a flat installation
plate section 64, and a hanging plate section 63 that is formed by
bending the inside edge of the installation plate section 64
downward. The shape and size of the outside surface (outer
perimeter surface) of this hanging plate section 63 is nearly the
same shape and size as the inside edge of the locking hole 45a.
Therefore, in this example, the rear end section of the hanging
plate section 63 is inclined in a direction such that the space
between them becomes narrower going toward the rear. Consequently
the hanging plate section 63 is fitted inside the locking hole 45a
such that there is hardly any space. With the hanging plate section
63 fitted inside the locking hole 45a, the bottom surface of the
installation plate section 64 is essentially placed on the top
surface of the bracket 11b on the vehicle side so that there is no
space between these surfaces except for any unavoidable small
spaces. Furthermore, the lower half section of the locking capsule
47 fits inside the hanging plate section 63, and with the bottom
surface of the flange section 48 in contact with the top surface of
the installation plate section 64 with essentially no space between
surfaces, the locking capsule 47 is assembled inside the locking
hole 45a by way of this sliding plate 62.
With the sliding plate 62 and the locking capsule 47 assembled
inside the locking hole 45a, the portion of the inside edge of the
locking hole 45a except the bottom end section is covered by the
hanging plate section 63. The lower end section is located in a
more recessed location than the hanging plate section 63.
Furthermore, the installation plate section 64 is held between the
bottom surface of the flange section 48 of the locking capsule 47
and the top surface of the bracket 11b on the vehicle side in the
portion that surrounds the locking hole 45a. A plurality of small
through holes 49a, 49b, 49c are formed in the portions surrounding
the flange section 48, locking hole 45a and installation plate
section 64 that are aligned with each other. By performing
injection molding to inject synthetic resin inside these small
through holes 49a 49b, 49c, and letting the synthetic resin
solidify, connecting pins 50 are formed so as to span between these
small through holes 49a, 48b, 49c. These connecting pins 50 are
connecting members that shear due to an impact load that is applied
during a secondary collision. In this way, the locking capsule 47
is connected and supported by the bracket 11b on the vehicle side
so that the locking capsule 47 can displace in the forward
direction due to an impact load that is applied during a secondary
collision.
With the steering column support apparatus of this example,
constructed as described above, it is possible to keep the load
required for causing the locking capsule 47, which is supported by
the steering column 6c by way of the bracket 33 on the column side,
to start coming out in the forward direction from the locking hole
45a, which is formed in the bracket 11b on the vehicle side, low.
In other words, in the case of the steering column support
apparatus of this example, a large portion of the inside edge of
the locking hole 45a is covered by the hanging plate section 63 of
the sliding plate 62, and the remaining portion is located in a
more recessed position than the hanging plate section 63.
Therefore, there is no direct rubbing between the surfaces on the
sides of the locking capsule 47 and the inside edges of the locking
hole 45a regardless of the direction in which the impact load that
is applied to the locking capsule acts during a secondary
collision.
Therefore, even when the inside edges of the locking hole 45a are
rough surface with exposed fractures, the friction force that acts
between the surfaces on the sides of the locking capsule 47 and the
opposing surfaces does not become large. Consequently, even when a
large diagonal force in the forward direction is applied from the
steering wheel 1 to the locking capsule 47 such as illustrated by
the X and Y arrows in FIG. 18, it is possible for the locking
capsule 47 to be separated from the bracket 11b on the vehicle side
smoothly by light force, thus more completely protecting the
driver. In the case of this example, as in the first embodiment,
the shape of the locking hole 45a and the rear end section of the
lower half section of the locking capsule 47 is such that the width
dimension becomes smaller going toward the rear, so the locking
capsule 47 can even more easily start to displace and come out in
the forward direction from the locking hole 45a, and thus it is
possible to even more completely protect the driver during a
collision accident.
Second Example of Third Embodiment
FIG. 21 illustrates a second example of the third embodiment of the
present invention. In this example, the locking grooves 53a that
are formed on both the left and right sides and the rear side of
the locking capsule 47b and the edge portion around the locking
hole 45a of the bracket 11b on the vehicle side engage. In other
words, this example uses a locking capsule that corresponds to the
locking capsule 47a in the construction of the first embodiment
illustrated in FIG. 5. However, taking into consideration the
placement of the sliding plate 62, the dimensions of the locking
groove 53a are similar to but a little smaller than the dimensions
of the locking hole 45a. More specifically, the width dimension of
the locking hole 45a is larger than the width dimension of the
locked section (middle section in the up/down direction) where the
locking groove 53a of the locking capsule 47b is formed, and 2
times the thickness dimension of the hanging plate section 63 of
the sliding plate 62 or greater. The construction and functions of
the other parts are the same as in the first example of the third
embodiment.
Third Example of Third Embodiment
FIG. 22 illustrates a third example of the third embodiment of the
present invention. In this example, the cross-sectional shape of
the sliding plate 62a is U shaped. In other words, the bottom plate
section 65 is bent from the edge of the bottom end of the hanging
plate section 63 of the sliding plate 62 in the same direction as
the installation plate section 64. The portion of the bracket 11b
on the vehicle side that surrounds the locking hole 45a is held
between the top surface of the bottom plate section 65 and the
bottom surface of the installation plate section 64. The
construction and functions of the other parts are the same as in
the section example of the third embodiment.
Fourth Example of Third Embodiment
FIG. 23 illustrates a fourth example of the third embodiment of the
present invention. In the case of this example, the locking hole
45b that is formed in the bracket 11c on the vehicle side is a
through hole that is not open on the front edge side of the bracket
11c on the vehicle side. The length dimension of this through hole
45b in the forward/backward direction of the bracket 11c on the
vehicle side is sufficiently larger than the length dimension of
the locking capsule 47. During a secondary collision, the locking
hole 47 is able to displace in the forward direction inside the
locking hole 45b within a range where the surface on the front end
of the locking capsule 47 does not come in contact with the inner
edge on the front end of the locking hole 45b. The construction and
functions of the other parts are the same as in the first example
of the third embodiment.
Fifth Example of Third Embodiment
FIG. 24 illustrates a fifth example of the third embodiment of the
present invention. In this example, a locking hole (locking notch)
45c is formed in the center section in the width direction of the
bracket on the vehicle side, and the aspect of the bracket 11d on
the vehicle side and the locking capsule 47 engaging in the center
section in the width direction of the bracket 11d on the vehicle
side is common with the other embodiments. However, in this
example, a pair of parallel open locking holes (locking notches)
45c that open on the edge of the front end of the bracket 11d on
the vehicle side are formed in the bracket 11d on the vehicle side,
and a pair of locking capsules 47c are locked in these locking
holes 45c. The construction and functions of the other parts are
the same as in the first example of the third embodiment.
Embodiment 4
FIGS. 27A to 27E illustrate five examples for reducing the break
away load as a fourth embodiment of the present invention. In other
words, in order to lessen the impact that is applied to the body of
the driver during a secondary collision, it is necessary to keep
the break away load, which is the load applied to the bracket on
the column side the instant that the bracket on the column side
begins to displace in the forward direction with respect to the
bracket on the vehicle side, low. In order to accomplish this,
making the friction state of the engagement section between the
locking capsule, which is fastened to the bracket on the column
side, and the bracket on the vehicle side a dynamic friction state
rather than a static friction state is effective.
First, the effect of making the friction state at the engagement
section between the locking capsule and the bracket on the vehicle
side a dynamic friction state rather than a static friction state
will be explained in reference to the construction illustrated in
FIG. 25 and FIG. 26 wherein the bracket on the column side is
supported by the bracket on the vehicle side at two locations on
both end sections in the width direction. In this construction, the
steering column 6e is supported by the center section in the width
direction of the bracket 12b on the vehicle side, and locking
capsules 19a are locked in cutout sections 15c that are formed in a
pair of installation plate sections 14c that are formed by bending
from the top end sections of the bracket 12b on the column side in
opposite directions from each other. The bottom end sections of a
pair of left and right support plate sections 34b of the bracket
12b on the column side are connected by way of connecting section
66 having low rigidity.
When an impact load is applied in the forward direction from the
steering column 6e to the support plate sections 34b, the
connecting section 66 and the installation plate sections 14c
displace from the state illustrated by the solid line in FIG. 26 to
the state illustrated by the dash line. As a result, the areas of
contact between the installation plate sections 14c and the locking
capsules 19a displace a little, and the friction states of these
areas of contact change from a static friction state to a dynamic
friction state. At the instant that these areas of contact change
to a dynamic friction state, the locking capsules 19a come out from
the cutout sections 15c. As is well known, the dynamic friction
coefficient is smaller than the static friction coefficient, so it
is possible to keep the force required for the locking capsules 19a
to come out low, or in other words, it is possible to keep the
break away load of the bracket 12b on the column side low.
This fourth embodiment of the present invention combines and
applies construction for changing the friction state of the
engagement section between the locking capsule, which is fastened
to the bracket on the column side, and the bracket on the vehicle
side from a static friction state to a dynamic friction state with
the other embodiments of the present invention. More specifically,
by alternatively applying the locking capsule or bracket on the
vehicle side having the construction described below to the
construction of the other embodiments, it is possible to
additionally obtain the effect of the fourth embodiment.
First, in the case of the construction illustrated in FIGS. 27A and
27B, the flange section 48a, 48b of the locking capsule 47d, 47e
and the bracket on the vehicle side are connected by a plurality of
connecting pins 50, 50a, 50b that shear due to an impact load that
is applied during a secondary collision. The strength of the
connection against this impact load between the locking capsule
47d, 47e and the bracket on the vehicle side that are connected by
these connecting pins 50, 50a, 50b is asymmetric on the left and
right side of the steering column. For example, in the case of the
construction illustrated in FIG. 27A the number of connecting pins
50 on the left and right differs. On the other hand, in the case of
the construction illustrated in FIG. 27B, the diameteres of the
connecting pins 50a, 50b on the left and right differ from each
other.
In the case of the construction illustrated in FIG. 27C, the
position where the bracket on the column side is connected and
fastened to the locking capsule 47f is shifted from the center
section in the width direction of the locking capsule 47f
illustrated by the dot-dash line .beta. in either direction in the
width direction, and in this example, is shifted to the left side
of the position in FIG. 27C.
On the other hand, in the case of the construction illustrated in
FIG. 27D, one of the inside edges of the left and right inside
edges of the locking hole 45d of the bracket 11e on the vehicle
side, or in other words, the inside edge on the left side in FIG.
27D, is parallel with the center axis of the steering column that
is expressed by the dot-dash line y, and the other inside edge, or
in other words, the inside edge on the right side in FIG. 27D, is
inclined in a direction going away from the one inside edge.
Furthermore, in the case of the construction illustrated in FIG.
27E, of the portion of the top surface of the bracket 11f on the
vehicle side that comes in contact with the bottom surface of the
flange section of the locking capsule, a sliding layer 67 made of a
low-friction material is provided on only the portion of one side
in the width direction of the locking hole 45e.
In the case of the construction of the five examples illustrated in
FIGS. 27A to 27E, the bracket on the column side and the locking
capsule displace in a twisting direction with respect to the
bracket on the vehicle side, or in other words, in a rotating
direction around a virtual center axis that is perpendicular to the
contact surface. More specifically, a force in a twisting direction
as described above is applied at the instant a secondary collision
occurs due to the difference in how easy the left and right
connecting pins 50, 50a 50b shear in the case of the construction
illustrated in FIGS. 27A and 27B, due to the impact load applied to
the locking capsule being unbalanced on the left and right in the
case of the construction illustrated in FIG. 27C, and due to the
difference in the friction force that acts between the edges on
both the left and right sides of the locking capsule and the inside
edges on the left and right of the locking hole in the case of the
construction illustrated in FIGS. 27D and 27E.
In the construction of the other embodiments of the present
invention, for example, the displacement due to this kind of force
in a twisting direction can be started with a small force when
compared with the break away load required to cause the locking
capsule to break away with respect to the bracket on the vehicle
side. The friction force that acts at the area of contact between
the bracket on the vehicle side and the locking capsule (and
bracket on the column side) changes from a static friction force to
a dynamic friction force due to this displacement. As a result, it
is possible to keep the break away force low. In this way, the
fourth embodiment of the present invention can additionally be
applied to the other embodiments of the present invention.
Embodiment 51
FIG. 28 to FIG. 30 illustrate an example of a fifth embodiment of
the present invention. The feature of this embodiment is improving
the operational feeling of the driver during normal operation by
improving the moment rigidity of the connecting section between the
bracket 33e on the column side and the locking capsule 47g by
devising the construction of the bracket 33e on the column side. By
alternating the construction of the bracket on the column side of
this fifth embodiment in the other embodiments of the present
invention, it is possible to additionally obtain the effect of this
embodiment. The construction and functions of other parts are the
same as in the first through third embodiments.
In the construction of the present invention, when the locking
capsule 47 and the bracket 33 on the column side having the
construction described above are connected and fastened by bolts
51, 51a and nuts 52, or by rivets 54, there is a possibility that
design freedom for increasing the pitch of these bolts 51, 51a or
rivets 54 is limited. In other words, not only is the pitch between
bolts 51, 51a limited from the aspect of the ability to insert this
rod shaped members on the inside of the locking hole 45 that is
formed in the bracket 11a on the vehicle side, but is also limited
from the aspect of preventing interference between the head
sections of these members and the end sections of the support plate
sections 34 of the bracket 33 on the column side. The space between
the inside surfaces of these support plate sections 34 is also
restricted by the portions fastened to the steering column that is
held between these support plate sections 34, or more specifically
by the space between the outside surfaces of the supported plate
sections 32.
Even when it is possible to increase the pitch between the rod
shaped sections of the bolts 51, 51a or rivets 54 that are located
on both the left and right sides by increasing the width dimension
of the locking hole 45 by a certain extent, there are cases where
the pitch still cannot be increased from the aspect of preventing
interference between the head sections and the support plate
sections 34. Not being able to increase the pitch between these
members is disadvantageous from the aspect of increasing the moment
rigidity in the left and right width direction. When this rigidity
is low, it becomes easy for the bracket 33 on the column side to
vibrate when travelling over a bad road. As a result, the steering
wheel 1 that is supported by the bracket 33 on the column side by
way of the steering column 6c and the steering shaft 5b vibrates,
giving an uncomfortable feeling to the driver who operates the
steering wheel 1.
In the following, an example of the fifth embodiment, which is a
preferred embodiment for improving this point, will be explained
centering on the feature of this embodiment. In the steering column
support apparatus of this example, the bracket 33a on the column
side is formed by combining a pair of bracket elements 68a, 68b
that are separate from each other. These bracket elements 68a, 68b,
except for small differences such as the length dimensions of the
long holes 35 in the up/down direction, have mirror symmetry, and
each is made by bending metal plate, such as carbon steel plate,
which has sufficient strength and rigidity. Each of these bracket
elements 68a, 68b comprises an installation plate section 69, an
inclined plate section 70 and a support plate section 34c. The
installation plate sections 69 are formed at the top end sections,
and are flat plates for coming in contact with the bottom surface
on both end sections of the locking capsule 47g such that there is
no movement between surfaces. The inclined plate sections 70 are
formed by bending from the inside edges of the installation plate
sections 69 (edges of the center side in the width direction that
face each other) toward the outside in the width direction
(opposite sides from each other) to an angle of more than 90
degrees, for example about 120 to 140 degrees so that the crossing
angles with the installation plate sections 69 become acute angles
of 40 to 60 degrees, such that they are inclined downward in a
direction toward the outside in the width direction. Furthermore,
the support plate sections 34c are formed so as to hang down from
the edges on the bottom ends of the inclined plate sections 70. In
the middle section in the forward/backward direction of the
connecting section between the installation plate sections 69 and
the inclined plate section 70, in a portion that does not interfere
with the bolts 51a, reinforcement ribs 71 are formed in order to
maintain the bending rigidity between the installation plate
sections 69 and the inclined plate sections 70.
The bracket elements 68a, 68b, each having an installation plate
section 69, inclined plate section 70 and support plate section 34c
as described above, are arranged such that the support plate
sections 34c are parallel with each other, and are connected and
fastened to the locking capsule 47g at a total of four locations,
two locations each in the forward/backward direction of the
installation plate sections 69, by bolts 51a and nuts 52, which are
rod shaped connecting members. In this state, the support plate
sections 34c become the portions that hold and support, from both
the left and right sides, a pair of supported plate sections 32,
which are formed on the bottom section of the outer column 24,
which forms the rear end section of the steering column 6c. In
order to prevent interference with the inclined plate sections 70,
bolts having a short dimension in the axial direction, and that
have a circular plate shape head section 61 are used as the bolts
51a. Furthermore, by using rivets 54 instead of the bolts 51a and
nuts 52, it is possible to even further reduce the height dimension
of the connecting section with these bracket elements 68a, 68b.
In the steering column support apparatus of this example, the
moment rigidity of the connecting section between the locking
capsule 47g and the bracket 33e on the column side that is a
combination of bracket elements 68a, 68b is increased, and thus it
is possible to improve the operational feeling of the steering
wheel 1. In other words, in this example, the bolts 51a are
arranged on the outsides of the inclined plate sections 70 (sides
opposite from each other) of the bracket elements 68a, 68b.
Moreover, the height dimension of each of the head sections 61 of
the bolts 51a is reduced, and these head sections 61 extend to the
back of the sections between the installation plate sections 69 and
the inclined plate sections 70.
By employing this kind of construction, in this example, it is
possible to suitably arrange the bolts 51a for connecting and
fastening the locking capsule 47g and bracket 33e on the column
side. In other words, it is possible to increase the pitch in the
width direction on the left and right of these bolts 51a, and thus
increase the moment rigidity in the left and right width direction
of the connecting section between the locking capsule 47g and the
bracket 33e on the column side. Moreover, by devising the shape of
the head sections 61, it is possible to arrange the bolts 51a in
positions directly above the support plate sections 34c even though
the crossing angles between the installation plate sections 69 and
the inclined plate sections 70 are acute angles. Therefore, with
the proper value for the width of the locking hole 45 that is
formed in the bracket 11a on the vehicle side being maintained
without the pitch P in the left and right width direction of these
bolts becoming excessive, it is possible to properly arrange the
bolts 51a. In other words, when attempting to increase the pitch P
in order to increase the moment rigidity of the connecting section
between the locking capsule 47g and the bracket 33e on the column
side, the size of the locking hole 45 does not have to be increased
more than necessary, so performing design using the optimal values
for the dimensional relationships of each of the parts becomes
easier.
In the case of the steering column support apparatus of this
example, with the dimensions of each part maintained at the optimal
values, sufficient pitch P in the left and right width direction of
the bolts 51a that connect the locking capsule 47g and the bracket
33e on the vehicle side is achieved, so it possible to sufficiently
increase the moment rigidity of the connecting section between the
locking capsule 47g and the bracket 33e on the column side.
Therefore, it is possible to increase the natural frequency
(resonant frequency) of the steering column 6c that is supported by
the bracket 33e on the column side even when travelling over bad
roads, so it becomes difficult for the steering wheel 1, which is
supported by the steering column 6c by way of the steering shaft
5b, to vibrate, and thus it is possible to avoid giving an
uncomfortable feeling to the driver who operates the steering wheel
1.
INDUSTRIAL APPLICABILITY
The case of applying the present invention to a steering column
support apparatus that comprises both a tilt mechanism for
adjusting the up/down position of a steering wheel, and a
telescopic mechanism for similarly adjusting the forward/backward
position of the steering wheel was explained. However, the present
invention can also be applied to a steering column support
apparatus that comprises only a tilt mechanism or only a telescopic
mechanism, and can be applied to a fixed steering wheel type
steering column support apparatus that does not comprise either of
these mechanisms.
TABLE-US-00002 [Explanation of Reference Numbers] 1 Steering wheel
2 Steering gear unit 3 Input shaft 4 Tie rod 5, 5a, 5b Steering
shaft 6, 6a, 6b, 6c, 6d, 6e Steering column 7 Universal joint 8
Intermediate shaft 9 Universal joint 10, 10a Housing 11, 11a, 11b,
11c, 11d, 11e, 11f Bracket on the vehicle side 12, 12a, 12b Bracket
on the column side 13 Bracket on the housing side 14a, 14b, 14c
Installation plate section 15a, 15b, 15c Cutout section 16a, 16b
Sliding plate 17 Energy absorbing member 18 Locking notch 19, 19a
Locking capsule 20, 20a Locking groove 21a, 21b Small locking hole
22 Locking pin 23 Inner column 24, 24a Outer column 25 Outer shaft
26 Ball bearing 27 Electric motor 28 Controller 29 Support cylinder
30 Center hole 31 Slit 32 Supported plate section 33, 33a, 33b,
33c, 33d, 33e Bracket on the column side 34, 34a, 34b, 34c Support
plate section 35 Long hole in the up/down direction 36 Long hole in
the forward/backward direction 37 Adjustment rod 38 Head section 39
Nut 40 Driving cam 41 Driven cam 42 Cam apparatus 43 Adjustment
lever 44 Friction plate unit 45, 45a, 45b, 45c, 45d, 45e Locking
hole (locking notch) 46 Installation hole 47, 47a, 47b, 47c, 47d,
47e, 47f, 47g Locking capsule 48, 48a, 48b, 48c, 48d Flange section
49a, 49b, 49c Small through hole on the capsule side 50, 50a, 50b
Locking pin 51 Bolt 52 Nut 53, 53a Locking groove 54 Rivet 55, 55a,
55b, 55c, 55d Top plate section 56 Bottom plate section 57, 57a
Extending section 58, 58a Convex curved surface 59 Through hole in
the circumferential direction 60 Protruding piece 61 Head section
62, 62a Sliding plate 63 Hanging plate section 64 Installation
plate section 65 Bottom plate section 66 Connecting section 67
Sliding layer 68a, 68b Bracket element 69 Installation plate
section 70 Inclined plate section 71 Rib
* * * * *